Steam-turbine.



PATENTBD MAY 9, 1905.-

. J. STUMPF.

STEAM TURBINE.

APPLICATION FILED FEB. 24, 1903. RENEWED SEPT. 9, 1904.

few $1 Mia NMED

Patented May 9, 1905.

JOHANN STUMPF, OF CHARLOTTENBURG, GERMANY, ASSIGNOR TO GEN- ERAL ELECTRIC COMPANY, A

CORPORATION OF NEW YORK.

STEAM-TURBlNE.

SPECIFICATION forming part of Letters Patent No. 789,462, dated May 9, 1905.

Application filed February 24, 1903. Renewed September 9, 1904. Serial No. 223,859.

To (I/Z/Z whom, it may concern.-

Be it known that I. JOHANN STUMPF, a subject of the King of Prussia, German Emperor, and a resident of 28 Rankestrasse, Charlottenburg, near Berlin, Kingdom of Prussia, German Empire, have invented certain new and useful Improvements in Steam-Turbines, of which the following is an exact specification.

My invention relates to improvements in steam-turbines, and more especially to such turbines as are provided with return-buckets, by means of which the steam leaving the turbine-wheel flows back into the buckets of the turbine-wheel.

Efforts have already been made to utilize the steam several times in one turbine-wheel by employing return-buckets without, however, being practically successful, for the reason that the flow of steam in the turbinewheel and the flow and streaming velocity of the same at the different places which the steam has to pass, as well as the cross-sections of the steam ports and passages, were not fully understood or considered, or both-that is to say, the wheel -buckets and return-buckets have not been given sufficient consideration, and in consequence thereof considerable losses arose due to shocks taking place in the turbine and also to the choking of the steam, so that the output of such turbines was sometimes smaller than in turbines in which the steam was only used once.

According to the present invention the steam passes back from the buckets of the turbine-wheel into return-buckets without any losses or detrimental choking of the steam. l. attain this object by the special construction of the return-buckets, which construction consists in making the admissionangles of the steam in the return-buckets different from the delivery-angles of the same. To state the matter in a different way, the admission-angle of the return-buckets is greater than the delivery-angle. By this means the cross-section of the steamjets at the discharge end of the return-buckets is considerably enlarged, and by reason of this difference between the admission and delivery angles the diminution in the velocity of flow of the steam during the passage of the same through the buckets is taken care of. Knowing the inclination of the wheel-buckets, the stream ing velocity of the steam leaving the buckets, and the circumferential velocity of the Wheel, the relative streaming velocity of the steam can be ascertained. From the data thus found the angle at which the steam has to enter the return-buckets (admission-angle) can be determined. Knowing the velocity of the steam leaving the return-buckets, the angle of inclination of the wheel-buckets, and the circumferential velocity of the turbine-wheel, the angle of inclination of the side of the retm'n-buckets, which leads the steam back to the wheel, can be easily determined. It will 5 be found that the ends or halves of the return-buckets have very different angles of inclination. The angle of inclination of the delivery end or half is much smaller than that of the admission end, and it will be clear that 7 the section of the discharge end of the returnbucket is much larger than the section of the ad mission end. By reason of this arrangement the steam is prevented from choking at the entrance of the return-buckets as it leaves the wheel. In consequence thereof no shocks can arise in the working of the turbine.

In order to make my invention more clear, I refer to the accompanying drawings, in which Figure 1 is partly a side view and partly a section of part of a turbine constructed according to my invention. Fig. 2is a plan thereof.

In the drawings is shown part of a turbinewheel provided with U-formed buckets, an 5 admission-nozzle, and a returnbucket. The steam enters through the nozzle 1) into the buckets a of the turbine-wheel and the broken and dotted line 0 shows the axis of the nozzle.

It will be seen that the nozzle is substantially 9 tangential to the rim of the wheel.

As may be seen from the plan in Fig. 2, the

nozzle 7) conducts the steam to the upper side of the buckets a, (when considering that figure.) The return-buckets (Z outside of the turbine-wheel receive the steam leaving the buckets a at the lower side of the same and bring the steam back to the upper side of the buckets a. The construction of the returnbueket (Z may be easily seen from Fig. 1. Within the buckets or shovels (Z ribs or partitions e are arranged, which run in the longitudinal direction of the buckets and which serve to guide the steam within the buckets (Z and to cause the whole cross-section of the return-buckets (Z to be filled with steam. The steam enters the horn or half (Z' of the returnbucket (Z and leaves the latter by the horn or half (Z of the same. It is easily seen from Fig. 1 that the angle of inclination of the horn (Z is much larger than that of the horn (Z and that the bucket as a whole covers the nozzle. It will further be seen from the drawings that although the admission end :0 of the return-bucket has a relatively large crosssection the cross-section of the delivery end y is considerably larger. The steam leaving the nozzle 6 flows in the direction indicated by the arrows 1, 2, 3, 4:, 5, and 6 in Fig. 201 the drawings. The steam leaving the nozzle 6 meets the turbine-wheel with a certain velocity. From this velocity and the circumferential velocity of the wheel the angle of inclination of the nozzle and of the wheelbuckets can be determined. In consequence of the utilization of the steam within the Wheel and of the friction of the steam the latter enters the return-buckets with a decreased velocity. It follows from this that the angle of inclination of the admission-horn (Z' of the bucket D must differ from that of the nozzle Z.

The guide-ribs or partitions e are for the purpose of insuring an equal division of the steam-jet over the whole breadth of the return-bucket,so that that part of the wheel upon Which the steam of the return-bucket is discharged receives a uniform jet of steam and choking of the steam at the end of the returnbucket is thereby entirely avoided. it is advantageous to close the horn (Z or even the whole bucket on the inside by means of a wall conforming to the U shape of the bucket, so that the walls of the bucket, the guide-ribs e, and these walls closing the buckets form rectangular channels which insure a proper guide for the steam. By thus inclosing the return-bucket the steam will be prevented from overflowing. It is to be understood that the nozzles and return-buckets may be duplicated ad Z'a'bz' t'um.

In accordance with the provisions of the patent statutes I have described the principle of operation of my invention, together with Further,

the apparatus which I now consider to represent the best embodiment thereof; but I desire to have it understood that the apparatus shown is only illustrative and that the invention can be carried out by-other means.

IV hat I claim as new, and desire to secure by Letters Patent of the United States, is

1. In an elastic-fluid turbine, the combination of a wheel having peripheral buckets, a nozzle situated adjacent to the buckets for discharging fluid against them, and a returnbucket which covers the nozzle and receives fluid from and discharges it against the wheel, the angle of the receiving portion being different from that of the discharge portion.

2. In an elastic-fluid turbine, the combination of a bucket-wheel, a nozzle situated adjacent to the buckets, which discharges fluid against them, and a return-bucket that is pro vided with horns, the said horns having unequal inclinations with respect to the buckets.

3. In an elastic-fluid turbine, the combination of a wheel having U-shaped buckets in the periphery, a nozzle substantially tangential to the periphery of the wheel, and a return-bucket which crosses the wheel and is provided with receiving and discharging horns, the latter presenting a greater area to the wheel than the former.

4. In an elastic-fluid turbine, the combination of a Wheel, a nozzle, and a return-bucket which crosses the rim of the wheel from one side to the other and is provided with horns having diflerent inclinations with respect to the wheel-buckets.

5. In an elastic-fluid turbine, the combination or a wheel having U-shaped buckets, a nozzle, and a return-bucket which receives exhaust fluid from one side of the said buckets and discharges it against angularly-displaced buckets located on the opposite side of the wheel, the return-bucket being provided with horns having diflerent inclinations with respect to the buckets and also unequal discharge areas.

6. In an elastic-fluid turbine, the combination of a wheel having U-shaped buckets at its rim, a nozzle tangentially arranged with respect to the wheel, a return-bucket having two horns, one of which occupies a plane coincident with that of the nozzle and the other a plane parallel therewith, and a support which is common to the nozzle and returnbucket.

7. In an elastic-fluid turbine, the combination of a bucket-wheel, a nozzle, a returnbucket which receives motive fluid from one side of the wheel and discharges it against buckets on the same wheel but angularly displaced, and a partition in the return-bucket to direct the fluid in its passage.

8. In a steam-turbine, the combination of IO having a receiving-orifice of less width than the buckets, and a discharge-orilice also of less Width than the buckets.

In testimony whereof I have signed my name to this specification in the presence of two subscribing Witnesses.

JOH ANN STUMPF.

Witnesses:

HENRY HAsPnR, WOLDEMAR HAUPT. 

